1) Field of the Invention
The present invention relates to a transparent resin laminate and a molded article used the same, and particularly to a transparent resin laminate with good adhesion between each resin layer, excellent in weather resistance, abrasion resistance, heat resistance and water resistance comprising polycarbonate resin base material/acrylic resin layer/cured layer and a molded article used the same. The transparent resin laminate and the molded article is applicable to the fields of windows, sun roofs and lamp covers for car, transparent roofs and dormer windows such as hothouse, soundproof walls, signboards, front boards of automatic selling machine, carports, optical materials such as spectacle lens and camera lens, guard sheets for indication of LCD and EL and membranes shielding oxygen and moisture.
2) Prior Art
Transparent organic plastic materials, particularly, a polycarbonate resin is applicable to various uses as optical materials because it is excellent in impact resistance, dimension stability, molding and fire self-extinguishing and has a high heat distortion temperature. However, they cause a problem that transparency of the most important property as a transparent material is impaired because surface hardness is low and abrasion resistance is poor.
Further, other transparent plastic materials, e.g., polymethylmethacrylate, polystyrene and polyvinyl chloride are applicable to various uses since they are excellent in transparency, light weight, easy molding and impact strength. However, molded articles also obtained from these materials cause problems that abrasion resistance, chemical resistance and solvent resistance are poorer than other materials and their surfaces are easily hurt.
In order to solve the above-mentioned problems, a polyorganosiloxane resin has been used as a coating to improve surface hardness and abrasion resistance of plastic molded articles such as a polycarbonate resin and an acrylic resin (Japanese Patent Kokai (Laid-open) No. 2-182764, 8-230127, 9-174783, 55-59929 and 58-107316).
However, when transparent plastics coated with a polyorganosiloxane resin are used outdoors, for example, in windows, sun roofs and lamp covers for car and vehicle, transparent roofs and dormer windows such as hothouse, spectacle lens and camera lens, coatings with performances capable of resisting to severe outdoor environments such as sunlight, rain, a humidity, a temperature difference between a high temperature and a low temperature are not yet sufficient in the present situation.
An object of the present invention is to solve the above-mentioned prior art problems and to provide a transparent resin laminate with good adhesion between each resin layer, excellent in weather resistance, abrasion resistance, heat resistance and water resistance and a molded article used the same.
As a result to solve the above-mentioned prior art problems, the inventors have found that a transparent resin laminate and a molded article used the same with good adhesion between each resin layer, excellent in weather resistance, abrasion resistance, heat resistance and water resistance and a molded article used the same can be obtained by using a resin laminate comprising an acrylic resin layer comprising an ultraviolet absorbent coated on at least one surface of a polycarbonate resin base material and a cured layer formed by coating a composition comprising polyorganosiloxane and specific ultraviolet absorbent in which a difference of linear expansion coefficient between each resin layer is made small, and have accomplished the present invention.
That is, the present invention provides a transparent resin laminate comprising a polycarbonate resin base material, an acrylic resin layer comprising an ultraviolet absorbent coated on at least one surface of said polycarbonate resin base material and a cured layer formed by coating a composition comprising polyorganosiloxane and a silicone-containing polymer ultraviolet absorbent on said acrylic resin layer and then curing, wherein a difference of linear expansion coefficient between said polycarbonate resin base material and said acrylic resin layer and a difference of linear expansion coefficient between said acrylic resin layer and said cured layer are 0/xc2x0 C. to 5xc3x9710xe2x88x925/xc2x0 C. respectively.
Further, the present invention provides a mold article for window glass and sun roof of car obtained by inserting the above-mentioned transparent resin laminate into a mold of an injection molder and injecting another polycarbonate resin to its polycarbonate resin base material side and then injection molding to integrate.
The present invention provides a molded article for window glass and sun roof of car obtained by bending the above-mentioned transparent resin laminate.
The present invention will be described in detail below.
The transparent resin laminate comprises polycarbonate resin base material/acrylic resin layer/cured layer.
It is preferable that the polycarbonate resin base material has a weight average molecular weight of 24000 to 53000. In the above-mentioned range of weight average molecular weight, its linear expansion coefficient is in the range of 6xc3x9710xe2x88x925/xc2x0 C. to 8xc3x9710xe2x88x925/xc2x0 C. The larger the weight average molecular weight of the polycarbonate resin is, the larger the linear expansion coefficient of the polycarbonate resin becomes.
The form of the polycarbonate resin material is a molded article, a film, a sheet or a board.
The cured layer is formed by coating a composition comprising a silicone-containing polyorganosiloxane and a polymer ultraviolet (hereinafter, xe2x80x9cUVxe2x80x9d) absorbent on the acrylic resin.
It is preferable that the polyorganosiloxane is a hydrolyzate and/or a partial condensed product obtained by hydrolysis and condensation of organosilane represented by the general formula R1nSi(OR2)4xe2x88x92n wherein n is an integer of 0 to 2 and it is a heat curing type.
R1 in the organosilane is an organic group having 1 to 8 carbon atoms. Examples of R1 include alkyl groups such as methyl group, ethyl group, n-propyl group, n-butyl group, i-butyl group, sec-butyl group, n-hexyl group and n-heptyl group, xcex3-chloropropyl group, vinyl group, 3,3,3-trifluoropropyl group, glycidoxypropyl group, xcex3-methacryloxypropyl group, xcex3-mercaptopropyl group, phenyl group and 3,4-epoxycyclohexylethyl group. R2 in the organosilane is an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms. Examples of R2 include methyl group, ethyl group, n-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, acetyl group, propionyl group and butyryl group.
Examples of the organosilane include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, xcex3-chloropropyltrimethoxysilane, xcex3-chloropropylethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, xcex3-glycidoxypropyltrimethoxysilane, xcex3-glycidoxypropyltriethoxysilane, xcex3-methacryloxypropyltrimethoxysilane, xcex3-methacryloxypropytriethoxysilane, xcex3-mercaptopropyltrimethoxysilane, xcex3-mercaptopropyltriethoxysilane, phenyl trimethoxysilane, phenyltriethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, 3,4-epoxycyclohexylethyltriethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, di-i-propyldimethoxysilane, di-i-propyldiethoxysilane, diphenyldimethoxysilane and diphenyldiethoxysilane, among which tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane and dimethyldiethoxysilane are preferable.
The organosilane can be used alone or in the combination of two species or more. Further, preferably 40 mol % or above and more preferably 50 mol % or above of the above-mentioned organosilane is CH3Si(OR2)3.
The organosilanes are hydrolyzed and condensed with a prescribed amount of water to change to oligomers. The organosilane monomer is about consumed and not present in the reaction system. Then, the reaction is further advanced so as to produce polyorganosiloxane substantially non-containing monomer and dimer and containing 65% by weight or above of hexamer or more and having a number average polymerization degree of 8 to 30.
When polyorganosiloxane thus obtained by the reaction substantially contains neither monomer nor dimer and contains 65% by weight or above of hexamer or more and has a number average polymerization degree of 8 to 30, the linear expansion coefficient of the cured layer formed by curing the polyorganosiloxane having said number average polymerization degree is in the range of 7xc3x9710xe2x88x925/xc2x0 C. to 15xc3x9710xe2x88x925/xc2x0 C. In the range of 65% by weight or above of hexamer or more and 8 to 30 of number average polymerization degree, the larger the content of hexamer or more or the number average polymerization degree is, the larger the linear expansion coefficient of the polyorganosiloxane becomes. It is possible to make small the difference of linear expansion coefficient between acrylic resin layer and cured layer so as to satisfy the range of linear expansion coefficient in the present invention considering the above-mentioned regard.
In the above-mentioned reaction, the reaction temperature is usually 25 to 70xc2x0 C., preferably 30 to 60xc2x0 C. and more preferably 30 to 50xc2x0 C. The post stage reaction is gradually advanced. When the reaction temperature is below 25xc2x0 C., it is not preferable since it takes along time to obtain intended oligomer components, whereas above 70xc2x0 C. it is not preferable since cross-link reaction sometimes occurs.
The hydrolysis of organosilane to obtain polyorganosiloxane to be used in the present invention can be performed by conventional processes. It is preferable to perform it in the presence of water containing an acidic hydrolysable catalyst. The catalyst for the above-mentioned hydrolysis can be selected from known catalysts to indicate an acidity of pH 2 to 5. For example, it is preferable to use acidic hydrogen halide, carboxylic acid and sulfonic acid, acidic or weak acidic inorganic salts or solid acids such as ion exchange resin.
Examples of the catalyst for hydrolysis include inorganic acids including, typically, hydrogen fluoride, hydrochloric acid, nitric acid, sulfuric acid, organic acids such as acetic acid and maleic acid, methyl sulfonic acid and a cation exchange resin having sulfonic acid group or carboxylic acid group on its surface. The amount of the catalyst for hydrolysis may be properly adjusted depending on various uses. In the present invention, it is preferable that it is in the range of 0.001 to 5 mol % to alkoxysilane.
A buffer solution to adjust pH including combinations of acid and basic compound such as a combination of acetic acid and sodium acetate and a combination of disodium hydrogenphosphate and citric acid, a dispersion solvent or an organic resin, a pigment, a dye, a leveling agent, UV absorbent and preservation stabilizer to provide excellent coating performances may be properly added.
In the composition comprising polyorganosiloxane in the present invention, a silicone-containing polymer UV absorbent is further contained. The silicone-containing polymer UV absorbent is a polymer obtained from (A) at least one UV absorbing monomer selected from the group consisting of benzophenone UV absorbing monomers represented by the following formula (1) and benzotriazole UV absorbing monomers represented by the following formula (2), (B) silicone macromer represented by the following formula (3), (C) functional group-containing copolymerizable vinyl monomer and (D) functional group non-containing copolymerizable vinyl compound and has a weight average molecular weight of 10,000 to 100,000; 
wherein R11 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms; R12 is an alkylene group having 1 to 10 carbon atoms or an oxyalkylene group having 1 to 10 carbon atoms and m1 is 0 or 1; R13 is a hydrogen atom or a low alkyl group and X1 is an ester bond, an amide bond, an ether bond or an urethane bond; 
wherein R21 is a hydrogen atom, a halogen atom or a methyl group; R22 is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms; R23 is an alkylene group having 1 to 10 carbon atoms or an oxyalkylene group having 1 to 10 carbon atoms and m21 is 0 or 1; R24 is an alkylene group having 1 to 8 carbon atoms or an alkylene group with an amino group having 1 to 8 carbon atoms or an alkylene group with a hydroxyl group having 1 to 8 carbon atoms and m22 is 0 or 1; R25 is a hydrogen atom or a low alkyl group and X2 is an ester bond, an amide bond, an ether bond or an urethane bond; 
wherein R31 is a hydrogen atom or a methyl group; R32 is an alkylene group having 1 to 6 carbon atoms or an oxyalkylene group having 1 to 6 carbon atoms and m31 is 0 or 1; R33 is an alkylene group having 1 to 6 carbon atoms, an alkylene group with an amino group having 1 to 6 carbon atoms or an alkylene group with a hydroxyl group having 1 to 6 carbon atoms and m32 is 0 or 1 and n is an integer of 1 to 200 and X3 is an ester bond or an amide bond.
In the present invention, it is preferable that a weight average molecular weight of (B) silicone macromer is 200 to 10,000.
In the present invention, each proportion of (A) ultraviolet absorbing monomer, (B) silicone macromer, (C) functional group-containing compolymerizable vinyl monomer and (D) functional group non-containing copolymerizable vinyl compound to total amount of components (A), (B), (C) and (D) is preferably (A)/(B)/(C)/(D)=5 to 50/5 to 60/50 to 80/5 to 20 (% by weight) and more preferably 10 to 30/10 to 30/60 to 70/10 to 15 (% by weight).
Examples of alkyl group having 1 to 6 carbon atoms (R11) in the formula (1) include methyl group, ethyl group, propyl group, isopropyl group, butyl group, s-butyl group, t-butyl group, pentyl group and hexyl group, among which an alkyl group having 1 to 4 carbon atoms is preferable and an alkyl group having 1 to 2 carbon atoms is more preferable. Examples of alkoxyl group having 1 to 6 carbon atoms (R11) include methoxy group, ethoxy group, propoxy group and butoxy group, among which an alkoxyl group having 1 to 4 carbon atoms is preferable and an alkoxyl group having 1 to 2 carbon atoms is more preferable.
R11 may be substituted in any position of a hydroxyl group-substituted benzene ring. Preferable substitution position is 3-site or 5-site.
Examples of alkylene group having 1 to 10 carbon atoms (R12, R23) in formula (1) and/or formula (2) include methylene group, ethylene group, trimethylene group, propylene group, tetramethylene group, pentamethylene group, hexamethylene group, octamethylene group and decamethylene group, among which an alkylene group having 1 to 6 carbon atoms is preferable and an alkylene group having 1 to 4 carbon atoms is more preferable. Examples of oxyalkylene group having 1 to 10 carbon atoms (R12, R23) include oxymethylene group, oxyethylene group and oxypropylene group.
R12 may be substituted in any position of a hydroxyl group-substituted benzene ring. Preferable substitution position of R12 is 4-site or 5-site and more preferably 4-site.
R23 may be substituted in any position of a hydroxyl group-substituted benzene ring. Preferable substitution position of R23 is 5-site.
Examples of low alkyl group (R13 and R25) include an alkyl group having 1 to 4 carbon atoms.
Examples of halogen atom (R21) include a fluorine atom, a chlorine atom and a bromine atom, among which a chlorine atom is preferable. When R21 is a halogen atom or a methyl group, R21 may be substituted in any position of benzene ring. Preferable R21 is a hydrogen atom.
In hydrocarbon group having 1 to 6 carbon atoms (R22), an alkyl group is preferable. Examples of such alkyl group include the above-exemplified alkyl group having 1 to 6 carbon atoms. R22 may be substituted in any position of a hydroxyl group-substituted benzene ring. Preferable substitution position of R22 is 3-site.
Examples of an alkylene group having 1 to 8 carbon atoms (R24) include the above-exemplified alkylene group having 1 to 8 carbon atoms, among which an alkylene group having 1 to 4 carbon atoms is preferable and an alkylene group having 1 to 2 carbon atoms is more preferable. Examples of an alkylene group with an amino group having 1 to 8 carbon atoms or an alkylene group with a hydroxyl group having 1 to 8 carbon atoms include the above-exemplified alkylene group with an amino group or a hydroxyl group.
Examples of X1 and X2 include xe2x80x94COOxe2x80x94, xe2x80x94OCOxe2x80x94, xe2x80x94NHCOxe2x80x94, xe2x80x94CONHxe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94NHCOOxe2x80x94 and xe2x80x94COONHxe2x80x94.
m1, m21 and m22 are 0 or 1. For example, when m1 is 0, X1 means to bond directly to a hydroxyl group-substituted benzene ring not through R12. That is, when m1, m21 or m22 is 0, R11, R23 or R24 is not present. When m1, m21 or m22 is 1, R11, R23 or R24 is present. For example, when m1 is 1, X1 means to bond to R12.
Examples of the benzophenone UV absorbing monomer represented by the above-mentioned formula (1) include 2-hydroxy-4-acryloyloxybenzohenone, 2-hydroxy-4-methacryloyloxybenzophenone, 2-hydroxy-4-(2-acryloyloxy)ethoxybenzophenone, 2-hydroxy-4-(2-methacryloyloxy)ethoxybenzophenone and 2-hydroxy-4-(2-methyl-2-acryloyloxy)ethoxybenzophenone.
Examples of benzotriazoles UV absorbing monomer represented by the above-mentioned formula (2) includes 2-[2xe2x80x2-hydroxy-5xe2x80x2-(methacryloyloxy)phenyl]benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(acryloyloxy)phenyl]benzotriazole, 2-[2xe2x80x2-hydroxy-3xe2x80x2-t-butyl-5xe2x80x2-(methacryloyloxy)phenyl]benzotriazole, 2-[2xe2x80x2-hydroxy-3xe2x80x2-methyl-5xe2x80x2-(acryloyloxy)phenyl]benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(methacryloyloxypropyl)-5-chlorobenzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(methacryloyloxyethyl)phenyl]benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(acryloyloyloxyethyl) phenyl]benzotriazole, 2-[2xe2x80x2-hydroxy-3xe2x80x2-t-butyl-5xe2x80x2-(methacryloyloxyethyl)phenyl]benzotriazole, 2-[2xe2x80x2-hydroxy-3xe2x80x2-methyl-5xe2x80x2-(acryloyloxyethyl)phenyl]benzotriazole, 2-[2xe2x80x2-hydroxy-5xe2x80x2-(acryloyloxybutyl)-phenyl]-5-methylbenzotrazole and [2-hydroxy-3-t-butyl-5-(acryloyloxyethoxycarbonylethyl)phenyl]benzotrazole
(A) UV absorbing monomer can be prepared by reacting an UV absorbing compound with a functional group(s) such as hydroxyl group, carboxyl group and amino group having 2-hydroxybenzophenone skeleton or 2-hydroxybenzotriazole skeleton with a copolymerizable vinyl compound such as acrylic acid and methacrylic acid to form a bond(s) such as an ester bond, an amide bond, an ether bond and an urethane bond.
(B) Silicone macromer is a silicone component-containing vinyl compound represented by the formula (3). Examples of an alkylene group having 1 to 6 carbon atoms (R32) or an oxyalkylene group having 1 to 6 carbon atoms (R32) in the formula (3) include the above-exemplified alkylene group or oxy alkylene group having 1 to 6 carbon atoms.
Examples of an alkylene group having 1 to 6 carbon atoms (R33) include the above-exemplified alkylene group having 1 to 6 carbon atoms, among which an alkylene group having 1 to 4 carbon atoms is preferable and an alkylene group 1 to 2 carbon atoms is more preferable. Examples of an alkylene group with an amino group having 1 to 6 carbon atoms or an alkylene group with a hydroxyl group having 1 to 6 carbon atoms include the above-exemplified amino group-or hydroxyl group-substituted alkylene group.
m31 and m32 are 0 or 1. n is an integer of 1 to 200 which shows a repeating number of silicone component or its polymerization degree.
Examples of X3 include xe2x80x94COOxe2x80x94, xe2x80x94OCOxe2x80x94, xe2x80x94NHCOxe2x80x94, and xe2x80x94CONH.
Examples of (B) silicone marcomer include 1-(3-methacryloxypropyl)polydimethylsiloxane, 3-methacryloxypropylpolydimethylsiloxane and polydimethylsiloxane methacrylamide. Examples of commercial (B) silicone macromer include Trade name xe2x80x9cSailaprene FM-0721xe2x80x9d and xe2x80x9cSailaprene FM-0725xe2x80x9d, each manufactured by Chisso Corpration in Japan.
The process for preparing (B) silicone macromer is not limited. For example, (B) silicone macromer can be prepared by esterification reaction of 1-(3-hydroxylpropyl)polydimethylsiloxane and acrylic acid or methacrylic acid, or by reaction of 2-hydroxyethylacrylate and 1-(3-glycidoxypropyl)polydimethylsiloxane.
The weight average molecular weight of (B) silicone macromer is not limited. It is preferable that it is 200 to 10,000 from the viewpoint of compatibility of silicone-containing polymer UV absorbent with a resin. Therefore, it is preferable that n of the formula (3) is about 1 to 130. It is more preferable that the weight average molecular weight of (B) silicone macromer is 500 to 5,000.
The (B) silicone macromer can be used alone or in the combination of two species or more.
The (C) functional group-containing copolymerizable vinyl monomer means a vinyl compound with a functional group(s) such as carboxyl group and hydroxyl group. The (C) functional group-containing copolymerizable vinyl compound is not limited and its examples include acrylic acid, methacrylic acid, maleic anhydride, 2-hydroxyethylacrylate, 2-hydroxylethylmethacrylate and diethyleneglycol monomethacrylate and can be used alone or in the combination of two species or more.
The (D) functional group non-containing copolymerizable vinyl compound means a vinyl compound having no functional group such as carboxyl group and hydroxyl group. In the present invention, a copolymerizable vinyl compound having a functional group(s) in copolymerizable vinyl compounds is included in (C) functional group-containing copolymerizable vinyl monomer and a copolymerizable vinyl compound having no functional group is included in (D) functional group non-containing copolymerizable vinyl compound. The (D) functional group non-containing copolymerizable vinyl compound can be used alone or in the combination of two species or more.
The (D) functional group-non containing is not limited and its examples include acrylate, methacrylate, alkyl vinyl ether, alkyl vinyl ester and styrene.
In more detail, examples of acrylate or methacrylate include C1-8 alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate and stearyl acrylate and C1-18 alkyl methacrylats such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, t-butyl methacrylate and 2-ethylhexyl methacrylate.
Examples of alkyl vinyl ether include C1-18 alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether and stearyl vinyl ether. Examples of alkyl vinyl ester include C1-18 alkyl vinyl esters such as vinyl acetate, vinyl propionate and vinyl butyrate.
The silicone-containing polymer UV absorbent can be prepared by conventional polymerization methods such as a solution polymerization method, a suspension polymerization method and an emulsion polymerization method. For example, when it is prepared by a solution polymerization method, monomer components of (A) UV absorbing monomer, (B) silicone macromer, (C) functional group-containing copolymerizable vinyl in monomer and (D) functional group non-containing copolymerizable vinyl compound are added to an organic solvent(s) and polymerization is performed in the presence of a polymerization initiator. The polymerization initiator is not limited.
The content of the silicone-containing polymer UV absorbent to polyorganosiloxane in the compositions is 0.5 to 10% by weight and preferably 1 to 5% by weight and more preferably 3 to 5% by weight. The content in the above-mentioned range does not exert influence on linear expansion coefficient of the cured layer.
The dispersion solvent can be used in the range not to impair the advantageous effects of the present invention. As the dispersion solvent, it is preferable to use water, low alcohols such as methanol, ethanol, isopropanol, n-butanol and isobutanol or ketones such as methylethylketone and diacetylketone. In order to develop the above-mentioned advantageous effects of solvent in the present invention, it is preferable to maintain water content in the corn position to 15% or below. When it is above 15%, stability of silanol group is deteriorated since water is selectively coordinated to silanol group.
The preservation temperature of the composition comprising polyorganosiloxane obtained herein is usually 25xc2x0 C. or below, preferably 15xc2x0 C. or below and more preferably 5xc2x0 C. or below. When it is above 25xc2x0 C., it is not preferable since hydrolysis and condensation reaction gradually proceed in a long time preservation.
Known cure catalyst, metal oxides and other additives may be properly added in the formation of a cured film with the composition comprising polyorganosiloxane of the present invention in order to improve hardness and abrasion resistance of the cured film and provide optical functions such as high refractive index.
Examples of cure catalyst include basic compounds such as lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, potassium acetate, sodium formate, potassium formate, n-hexylamine, potassium propionate, tributylamine and diazabicycloundecene, metal compounds such as tetraisopropyltitanate, tetrabutyltitanate, aluminum triisobutaoxide, aluminum triisopropoxide, xcex3-aminopropyltrimethoxysilane, aluminum acetylacetonate aluminum perchlorate, aluminum chloride, cobalt octylate, cobalt acetylacetonate, iron acetylacetonate, tin acetylacetonate and dibutoxy tinoctylate, acidic compounds such as p-toluene sulfonate and trichloro acetate. It is preferable that the amount of the cure catalyst is 0.01 to 10 parts by weight to 100 parts by weight of the composition comprising polyorganosiloxane.
Examples of metal oxide include silica, alumina, titanium oxide, cerium oxide, tin oxide, zirconium oxide, antimony oxide and iron oxide. Particularly, when it is used as a curing coating intended abrasion resistance, colloidal silica (silica sol) is preferable. When metal oxide is used as a curing coating, its amount is 5 to 500 parts by weight and preferably 10 to 200 parts by weight to 100 parts by weight of polyorganosiloxane resin. Condensation reaction may be performed in the presence of metal oxide or it may be added after condensation reaction.
The methods for coating the composition comprising polyorganosiloxane include brushing, rolling, dipping, flow coating, spraying, roll coater, flow coater, centrifugal coater, ultrasonic coater, screen process, electrolytic deposition coating and vapor deposition coating, depending on their purpose.
The acrylic resin layer positioned between the polycarbonate resin base material and the cured layer of the composition comprising polyorganosiloxane will be described in detail below.
It is preferable that an acrylic resin in the acrylic resin layer contains 80 mol % or above and preferably 80 to 99 mol % of a monomer of methylmethacrylate structural unit to total monomers of all structural units and has a weight average molecular weight of 70000 to 150000. When the acrylic resin is a homopolymer of methylmethacrylate, its heat stability is poor. In the above-mentioned range of the structural unit amount of methylmethacrylate and weight average molecular weight, the linear expansion coefficient is in the range of 5xc3x9710xe2x88x925/xc2x0 C. to 9xc3x9710xe2x88x925/xc2x0 C. The larger the structural unit monomer amount of methylmethacrylate is, the small the linear expansion coefficient of acrylic resin layer becomes. It is possible to make small both the difference of linear expansion coefficient between the polycarbonate resin base material and the acrylic resin layer and the difference of linear expansion coefficient between the cured layer and the acrylic resin layer and to maintain it within the range of the present invention, considering the structural unit monomer amount of methylmethacrylate in the acrylic resin and its weight average molecular weight.
It is preferable that the acrylic resin comprises methylmethacrylate unit as main component and the acrylic resin is a copolymer of methylmethacrylate with methylacrylate, ethylacrylate or butylacrylate. It is preferable to mold a polycarbonate resin and an acrylic resin by coextrusion. The heat deformation temperature is 90xc2x0 C. or above, preferably 95xc2x0 C. or above and more preferably 100xc2x0 C. or above since when heat resistance of an acrylic resin is deteriorated, problems such as scorching and heat decomposition are caused during coextrusion molding.
The process for producing an acrylic resin is generally classified mainly into a process for emulsion polymerization process, a suspension polymerization process and a homogeneous polymerization process. It is preferable that the acrylic resin to be used in the present invention is an acrylic resin used by a homogeneous polymerization process. The homogeneous polymerization process is further classified into a continuous bulk polymerization process and a continuous solution polymerization process. In the present invention, an acrylic resin obtained by either one of the processes can be used.
In the emulsion polymerization process and the suspension polymerization process, an emulsifier or a suspension dispersant is used during polymerization reaction. After the completion of the polymerization reaction, these additives are removed by washing in water washing step. It is difficult to remove completely them. For example, In the appearance of a laminated sheet produced by coextrusion of an acrylic resin (Parapet HR-L) manufactured by suspension polymerization and a polycarbonate resin, occurrence of a large amount of eruptions and stripes was observed. As a result of analysis of microscopic IR for these eruptions, it was assumed that they were generated due to a suspension dispersant mixed therein in a small amount since its IR chart was an IR chart different from both the acrylic resin and the polycarbonate resin. The stripes were present in an interface between the acrylic resin layer and the polycarbonate resin layer and observed as foreign substances due to difference of refractive index. It was considered that the stripes occurred from the eruptions in a dye head as a base point.
On the other hand, in the continuous bulk polymerization process or in the continuous solution polymerization process, no the above-mentioned additives are used. A polymerization initiator and a chain transfer agent to adjust molecular weight are merely added. In the continuous solution polymerization process, examples of solvent include toluene, ethylbenzene, xylene, hexane, octane, cyclohexane, methanol, ethanol, propanol, butanol, acetone and methylethyl ketone, to which the present invention is not limited in the present invention. The solvent which can carry out effectively the polymerization reaction and does not remain in obtained acrylic resin may be used.
As the polymerization initiator, conventional azo polymerization initiators or peroxide polymerization initiators are effectively selected. Various polymerization initiators described in catalogues of NOF Corporation, Wako Pure Chemical Industries, Ltd., and Kayaku Akzo, K. K., in Japan can be used.
Examples of azo polymerization initiators include 2,2xe2x80x2-azobisisobutyronitrile, 2,2xe2x80x2-azobis(2-methylbutyronitrile) and 1-1xe2x80x2-azobis(cyclohexane-1-carbonitrile) and examples of peroxide polymerization initiators include benzoyl peroxide, di-t-butyl peroxide and di-t-amyl peroxide, to which the present invention is not limited.
As the chain transfer agent, mercaptans are usually used. Various mercaptans described in the catalogues of Kao Corporation and NOF Corporation, in Japan can be used, Examples of mercaptans include butyl mercaptan, hexyl mercaptan, octyl mercaptan and dodecyl mercaptan, to which the present invention is not limited.
These polymerization initiators and chain transfer agents cause no problems of eruptions and stripes because they are present in an end(s) of an acrylic polymer. Decomposed substances of a polymerization initiator which did not bond on an end(s) of the polymer do not cause the above-mentioned problems because they are dissolved in the acrylic polymer. Unreacted mercaptans are about perfectly removed in a step for volatilizing unreacted monomers and solvents. Mercaptans remained in very small amount do not cause the above-mentioned problems because they are perfectly dissolved in the acrylic resin and the polycarbonate resin.
An UV absorbent(s) of 0.01 to 5% by weight, preferably 0.02 to 3.5% by weight and more preferably 0.05 to 3.0% by weight may be contained in the acrylic resin in order to maintain weather resistance for a long time. In its content of the above-mentioned range, the addition of UV absorbent exerts no influence on the linear expansion coefficient of the acrylic resin layer. Known antioxidants and color resisting agents in addition to UV absorbent may be added to the acrylic resin layer. When the amount of UV absorbent is below 0.01% by weight, satisfactory weather resistance is not exhibited. When it is above 5% by weight, not only further improvement of weather resistance cannot be expected, but also these additives cause bleeding-out, so that whitening is caused and failure of adhesion and deterioration of mechanical properties, particularly impact strength may occur.
Examples of UV absorbent to be added to the acrylic resin include UV absorbents of benzotriazoles, benzophenones, phenyl salicylates and triazines, which can maintain transparency of the acrylic resin layer.
Examples of benzotriazole UV absorbents include 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(xcex1,xcex1-dimethylbenzil)phenyl]-2H-benzotrialzole, 2-(2xe2x80x2-hydroxy-5xe2x80x2-t-octylphenyl) benzotriazole and 2,2-methylenebis[4-(1,1,3,3,3-tetramethylenebutyl)-6-(2H-benzotriazole-2-yl)phenol.
Examples of benzophenone UV absorbents include 2-hydroxy-4-octoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-4xe2x80x2-chlorobenzophenone, 2,2-dihydroxy-4-methoxy-benzophenone and 2,2-dihydroxy-4,4xe2x80x2-dimethoxy-bezophenone.
Example of phenyl salicylate UV absorbent includes p-t-butylphenyl salicylate.
Examples of triazine UV absorbents include 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2-4-diphenyl-6-(2-hydroxy-4-ethoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-dodecyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-benziloxyphenyl)-1,3,5-triazine and 2,4-diphenyl-6-(2-hydroxy-4-butoxyethoxy)-1,3,5-triazine.
Further, generally obtainable antioxidant and color resisting agent are contained in the acrylic resin layer.
As antioxidants and color resisting agents to be added to the acrylic resin layer, various antioxidants and color resisting agents described in the catalogues of Ciba Specialty Chemicals K. K., Sumitomo Chemical Co., Ltd., and Asahi Denka Kogyo K. K., in Japan can be used.
Examples of antioxidants and color resisting agents include 2,6-di-t-butyl-4-methyl phenol, 2,2xe2x80x2-methylenebis(4-methyl-6-t-butylphenol), 2,2xe2x80x2-methylenebis(4-ethyl-6-t-butylphenol), 3,3xe2x80x2,3xe2x80x3,5,5xe2x80x2,5xe2x80x3-hexa-t-butyl-a,axe2x80x2,axe2x80x3-(mesitylene-2,4,6-tolyl)tri-p-cresol, ethylenebis(oxyethylene)bis[3-(5-t-butyl-4-hydroxy-m-tolyl)propionate], hexamethylenebis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,6-di-t-butyl-4-[4,6-bis(octythio)-1,3,5-triazine-2-yl-amino]phenol, pentaerythritoltetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,Nxe2x80x2-hexane-1,6-diyl-bis[3-(3,5-di-t-butyl-4-hydroxyphenylpropionamide)], 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzil)-1,3,5-triazine-2,4,6(1H,3H,5H)-trion, 1,3,5-tris[(4-t-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-trazine-2,4,6(1H,3H,5H)trion, diallyl-3,3xe2x80x2-thiodipropionate, pentaerythrityltetrakis (3-laurylthiopropionate), tris(nonylphenyl)phosphite, tris(dinonylphenyl)phosphite, 4,4xe2x80x2-thiobis(3-6-t-butylphenol), thiodiethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], trisnonylphenyl phosphite, triphenyl phosphite and tris(2,4-di-t-butylphenyl)phosphite and further PEP4C, PEP8, PEP24G, PEP36 and HP-10 described in the catalogue of Asahi Denka Kogyo K. K., in Japan, to which the present invention is not limited.
In the coextrusion of the polycarbonate resin and the acrylic resin, a lubricant to be added for the purposes of moldability with a feed black, a T-die and prevention of rolling in a polishing roll is 0.1 to 1% by weight, preferably 0.2 to 0.8% by weight and more preferably 0.2 to 0.7% by weight to the acrylic resin. When the amount of a lubricant is below 0.1% by weight, it does not contribute to improvement of adhesion to a roll, so that sufficient effect is not exhibited, whereas above 1% further improvement effect of mold ability is not exhibited, so that the lubricant causes bleeding out to deteriorate sometimes surface property of a laminate such as dust adhesion, and failure of adhesion to coating in the following step. As the lubricant to be added to the acrylic resin, various lubricants described in the catalogues of Kao Corporation, NOF Corporation, and Asahi Denka Kogyo K. K., in Japan can be applied. Examples of the lubricants include esters such as butylstearate, alcohols such as stearyl alcohol, glycerides such as stearic acid monoglyceride, sorbitans such as sorbitan monopalmitate and sorbitan monostearate, polyhydric alcohols such as mannitol, fatty acids such stearic acid, fat and oil type waxes such as cured castor oil, amides such as stearic acid amide and oleic acid amide, bisamides such as ethylenebis stearic acid amide and composite lubricants.
The film thickness of the acrylic resin layer produced by coextrusion is 1 to 100 xcexcm, preferably 3 to 80 xcexcm and more preferably 5 to 50 xcexcm. When it is below 1 xcexcm, the effect is not exhibited, whereas above 100 xcexcm impact strength of a polycarbonate resin sometimes remarkably deteriorated and furthermore economy is disadvantageous.
An example of the process for producing the resin laminate of the present invention is described below.
An extruder to be used for production of the laminate generally comprises one main extruder to extrude a polycarbonate resin as the base material layer and at least one subextruder to extrude an acrylic resin as a coating layer. As the subextruder, a smaller type extruder than the main extruder is applied. The temperature conditions of the main extruder are usually 230 to 290xc2x0 C. and preferably 240 to 280xc2x0 C. The temperature conditions of the subextruder are usually 220 to 270xc2x0 C. and preferably 230 to 260xc2x0 C. As methods for coating two species or more of molten resin, known methods such as a feed block method and a multimanifold die method can be applied. In this case, molten resins laminated by feed block are introduced to a sheet molding die such as T die and molded into a sheet form and then transferred to a molding roll (polishing roll) subjected to mirror treatment for its surface to form a bank. The sheet type molded article is subjected to mirror finishing and cooling while passing the molding roll, whereby a laminate is formed. In case of multimanifold die, molten resins laminated in the die are molded to a sheet form inside the die and then subjected to surface finishing and cooling in a molding roll, whereby a laminate is formed. The temperature of die is usually 220 to 280xc2x0 C. and preferably 230 to 270xc2x0 C. The temperature of molding roll is usually 100 to 190xc2x0 C. and preferably 110 to 180xc2x0 C. A longitudinal type roll or a horizontal type roll may be properly applied.
The most important feature of the resin laminate of the present invention is to make small the difference of linear expansion coefficient between each resin layer. In the present invention, the difference of linear expansion coefficient between the polycarbonate base material and the acrylic resin layer and the difference of linear expansion coefficient between the acrylic resin layer and the cured layer, are respectively 0/xc2x0 C. to 5xc3x9710xe2x88x925/xc2x0 C. and preferably respectively 0/xc2x0 C. to 3xc3x9710xe2x88x925/xc2x0 C. The small the difference of linear expansion between the polycarbonate resin base material and the acrylic resin layer and the difference of linear expansion coefficient between the acrylic resin layer and the cured layer is, the better adhesion between each layer can be maintained. Excellent weather resistance can be attained by maintaining good adhesion between each resin layer.
The linear expansion coefficient of each resin layer can be properly selected so as to satisfy the above-mentioned range of the difference of linear expansion coefficient between each resin layer in the present invention, considering the relation between molecular weight and linear expansion coefficient of a polycarbonate resin, the relation between monomer content of methylmethacrylate structural unit in an acrylic resin and linear expansion coefficient of an acrylic resin and the relation between amount of hexamer or more and average polymerization of polyorganosiloxane before curing and linear expansion coefficient of polyorganosiloxane.
When the resin laminate has a thickness of 1 mm or below, it is installed to at least one mold of an injection molder so as to face its cured layer to the surface of the mold and another polycarbonate resin is injected in a cavity of the mold and cooled, whereby molding is performed.
When the resin laminate has a thickness of 3 mm or above, molding is performed by bending.
The molded thus obtained are applied mainly to window glasses and sun roofs for car.
The present invention will be described in more detail below, referring to Examples, which are not intended to limit the scope of the present invention, Further, the word xe2x80x9cpartxe2x80x9d means xe2x80x9cpart by weightxe2x80x9d and the word xe2x80x9c%xe2x80x9d means xe2x80x9c% by weightxe2x80x9d except particular designation.
The evaluation method and the test method used in Examples and Comparative Examples are shown below.
The measurement was performed according to JIS K7197. A sample (1 mm or abovexc3x971 mm or abovexc3x97100 xcexcm to 5 mm) was placed on a quartz board and a cylindrical rod of cross section area 0.53 mm2 was placed thereon. The temperature was raised at the rate of 10xc2x0 C./min. Thus, the measurement was performed.
(Preparation of Polyorganosiloxane Sample)
3 g of a composition comprising polyorganosiloxane was weighed in an aluminum cup and standing on a hot plate of about 45xc2x0 C. for 2 hours to remove volatile components. Then, curing was performed in a dryer of 125xc2x0 C. for 2 hours and then cured product thus obtained was peeled off from the aluminum cup, whereby the sample of about 3 mmxc3x97about 3 mmxc3x97thickness about 100 xcexcm was prepared.
(Preparation of Polycarbonate Resin Sample)
A polycarbonate resin sheet of thickness 5 mm was cut into the size of about 3 mmxc3x97about 3 mm and cut surfaces was smoothed with a cutter knife, whereby the sample was prepared.
(Preparation of Acrylic Resin Sample)
Both cross sections of a polymethylmethachylate pellet of about xcfx86 3 mmxc3x97about 5 mm was microtome cut to chamfer, whereby the sample was prepared.
Volatile components comprising water as main component and organic solvents such as alcohols and acetylacetone were removed from 5 g of a composition solution comprising polyorganosiloxane in an ice bath under a reduced pressure of 10 mmHg or below. Then, the composition thus removed volatile components was dissolved in THF to prepare a solution of 0.1% concentration and then passed through a membrane filter of 0.1 xcexcm, and then GPC analysis was performed.
A polymer UV absorbent was dissolved in THF to prepare a solution of 0.2% concentration and then passed through a membrane filter of 0.1 xcexcm and then GPC analysis was performed.
Column: ┌TSKGel GMHXL┘xc3x972+┌TSKGel G2000HXL┘
xc3x971, manufactured by Toso k. k., in Japan
Transfer layer: THF
Sample concentration: 0.1% THF
Oven temperature: 40xc2x0 C.
Detector: ┌UV-8000┘ manufactured by Tosoh
Corporation, in Japan
An acrylic resin or a polycarbonate resin was dissolved in THF to prepare a solution of concentration 0.3% and then passed through a membrane filter of 0.1 xcexcm and then GPC analysis was performed.
The measurement was performed using polystyrene as a standard polymer by GPC apparatus, manufactured by Waters Co.(column: Ultrastalizel 105+104+103+500 xc3x85, manufactured by Waters Co.). Then, a weight average molecular weight was determined from a calibration curve determined the relation between dissolution time and molecular weight of acrylic resin or polycarbonate resin by a universal calibration method.
The test was conducted in a cycle of light irradiation for 5 hours (UV intensity 50 mW/cm2, black panel temperature 63xc2x0 C. and humidity 50%) and dewing for one hour (temperature 30xc2x0 C. or above and humidity 100%) with a super UV tester, manufactured by Iwasaki Denki K. K., in Japan and furthermore showering was performed for 10 seconds every 10 minutes during light irradiation. The change of appearance such as crack and natural peeling at each time was observed. xe2x80x9cNo changexe2x80x9d was judged as xe2x80x9cpassedxe2x80x9d.
Haze under a load of 500 g after 500 rotation measured with Taber abrasion tester in stalled abrasion ring CS-10F according to ASTM 1044. The value (xcex94H %) deducted a value prior to testing was indicated.
According to JIS K5400, each six longitudinal and horizontal rifts in 2 mm interval were inserted into a sample with a razor edge to make 25 cross hatch squares and then sufficiently adhered to a commercial cellophane tape. When the cellophane tape was suddenly peeled off to this side of 90 degree, the number of square remained with out being peeled off was represented by X/25.
The measurement was performed by a hazemeter 80-NDH, manufactured by Nihon Denshoku Kogyo K. K., in Japan.
A sample was immersed in a boiling water of 100xc2x0 C. for 2 hours and then change of appearance and adhesion were evaluated.
A sample was standing in hot wind circulation dryer of 130xc2x0 C. for one hour and then change of appearance and adhesion were evaluated.